add directory study

study/linux-travel/minix-386/estdio21.tar/estdio21/_rlbf.c

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+/*                                _ r l b f                                */
+
+/* This function provides line buffered read support. When reading
+ * from a line buffered stream, it is necessary to discard any
+ * readahead. This function is dynamically linked to __Zrlbf by
+ * setvbuf to minimise code size when line buffered input is not
+ * required.
+ *
+ * This function scans the input buffer and returns a shortened
+ * buffer size. If no \n is found, the buffer size is returned.
+ */
+
+#include "stdiolib.h"
+
+/*LINTLIBRARY*/
+
+__stdiosize_t __rlbf F2(register FILE *, fp, register __stdiosize_t, bytes)
+
+{
+  __stdiobuf_t *nlp;			/* \n pointer */
+  int offset;				/* offset back to one past \n */
+  
+  return ((nlp = (__stdiobuf_t *) MEMCHR(fp->__base, '\n', (size_t) bytes))
+						      != NULL &&
+          (offset = nlp - (fp->__base + bytes) + 1)   != 0    &&
+          lseek(fileno(fp), (off_t) offset, SEEK_CUR) != -1L)
+         ? bytes + offset : bytes;
+}